sandell



H. K. SANDELL..

RECTIFYING ALIEN/mwa CUMENTS` 2 sHEEsfgHEET 1,

` l H'. msANDELL. RECTIFYlNG ALTERNATING CURQENTS.

nvm-CANON mio wrm is. 19u.

,"Patnted July l; 1919.

swims-SHEET '2..

Stklon lying above the battery 'the instance gwen this may amount to approximately of the entire wave.

these circumstances.

and of a cross-sectional area of S square inches; being 2 inches in depth and l inches in' W1dth. The primary winding 12 consists of a single layerof square conductor aggregating 150 turns, while the secondary Windl3 hkewlse consists of asmgle layer agcross-section wound, through their entire` length with a single layer of primary and a single layer of secondary'.

I am of the opinion thatthe peculiar transformer design found by me to be essential to the etliciency of the rec-tifying system described is accounted for by the follmving characteristics of that system. In the example given, i. e., the. charging of a 10U-jolt storage battery from rectified alternating current of a voltage of 1107 it is appareutthat the commutation and control must be such as to malte use of only a. small portion of the alternating current Wave, 2'. e., that porvoltage. In

Now, in order to maintain an average current flow through the battery circuit of any reasonable value, it is therefore necessary that the actual current flow during the fraction of time when the circuit is closed through the commutator to the battery must be very high, approximately four times the nominal or average current. Two peculiar transformer effects would appear to result from In the first instance, the transformer is required to become loaded and unloaded in a time approximately -l of that nominally necessary as determined by the frequency of the current. In the second instance, the transformer must furnish during this exceedingly brief interval of time in which it is loaded and again unloaded, a current which over that time must have yan average value of approximately l times the nominal current value inthe charging circuit.

The foregoing vconsiderations led me to the conclusion, the results of which 'are elnlmdied inA the transformer specifically described and illustrated above. This transformer I find to operate satisfactorily and etliciently in connection with the rectifying system disclosed.

vWhat I claim as new and desire to secure by Letters Patent, is:'-

1. The combination with a commutator reetifying system of a transformer for supplying alterating current to the rectifying commutator thereof, said transformer haring a core member proportioned to operate at low-flux density and single turn primary and secondary windings distributed on such core member.

2. A transformer for use in a commutator rectifying system, a cdre member propon tioned to operate at low-flux density and comprising short yoke members, relatively long leg members and single turn primary and secondary windings distributed on each leg member.

3. A closed rectangular core type transformer having leg members and yoke members. the leg member vbeing more than twice the length of the yoke members, measured along the sides of the Windonv and the cross section of the leg members being eight square inches,A and single turn primary and secondary windings distributed throughout the length of cach leg member.

HENRY K. SANDELL. 

